Oil burner



Aug. 12, 1941. a. F. CROSIAR OIL BURNER Filed Jan. 26, 1939 Patented Aug. 12, 1941 UNITED j STATES ATE-NT QFFICE A *j P 2,252,556 b OIL BURNER Glenn Grosiar, Chicago, Ill. Application January 26, 1939, Serial No. 252,947 2 Claims (01. 15836) This specificatiohis a continuation in part of application Serial No, 156,824, filed July 31, 1937. The oil burner of the present invention is designed primarily for the burning of heavy oils which require p'reheating and commingly with a blast of air prior to ignition; and the object of the present invention is to combine in a compact self-contained formthe featuresof construction required" in the preparation of the oil for discharge and ignition; l I

A'further object of the invention is to conserve to the greatest possible extentrthe heat 'units required in preheating, and also to make provision for heating the oil during the ch period, so that when, the oil is thereafter ignited the noi'zle will not deliver an excess amount of oil wl iich might create a hazardous over firing in the boiler or furnace or create a disagreeable pulsating-1 f v A fnrther object of the invention lsto prevent the oilpassing through the oil line from being cooled down by cold air delivered from the fan andfthrough the draft tube, and otherwise conserve theheat so" that the oil will be in the proper condition as to temperature and volume of discharge at the instant of ignition.

The invention also relates to the means pro vided forregulatingthe pressure Within the oil line and tothe utilization of heated oil released from the'oil line under excess pressure for preheating purposes.

Further objects and details will appear from the description of the invention in conjunction with the" accompanyingdrawing, wherein- Figure l is a sectional elevation of the device of the present invention in the form which iitili'zes a relief valve for regulating the oil pressureyand: 3 Fig. 2 isa sectional view of the oil line and surrounding jacket removed from the air blast tube in a form which omits the relief valve. The device as a whole comprises an inner oil supply tube I'll which is surrounded by a jacket tube I I through which a heating medium is cir collated for the purpose of preheating the oil within the oil supply tube. The tube and jacket are arranged concentrically, or nearly so, sothat an annular chamber is provided around the oil supply tube from end to end thereof. The jacket with the enclosed tube are housed Within an elongated draft tube I2 which mounts a blower 13 for delivering air into the interior of the draft tube."

The oil supply tube at its forward end is threaded into a fitting M, which may include a relief valveof the character shown in Fig; 1 or may be of the simplified construction shown in Fig. 2. The fitting of Fig. 1 is provided with an oil supply duct [5 which communicates with a valve chamber lewithin which is located a valve stem ll, carrying at its rear end a valve head l8 which is normally held seated within the rear end of the valve chamber by the action of a relief spring I 9 which is adjustable by means of a screw 20. The spring is located within a relief chamber 2! into which enters a port 22 leading to an annular chamber 23 into which is screwed the forward end of the jacket tube I.

The arrangement is one which permits excessive pressure to force back the relief valve IE to The oil under pressure enters the apparatus.

through a supply pipe 25 which discharges into a preheater drum 26 which in the form shown is provided with an electric resistance element 2'! for heating the oil. It will be understood, hot-vever, that if desired the oil entering through the pipe 25 may be previously or otherwise heated to any desired extent by means which form no part of the present invention.

The provision of the heater 21, however, permits the oil to be heated to the desired degree in advance of ignition, so that there will be no preliminary excessive discharge of oil which might otherwise occur, especially where an atomizing nozzle is employed which requires a discharge of oil of relatively low viscosity in order to impart intended speed of rotation to the oil to regulate and restrict its discharge and atomization, in the intended manner.

The oil in the preheater, in the form here shown, is delivered through a pipe-liheZB which has its intake from a point closely adjacent to the heating eIementiZ'l. The deliveryend or" the oil pipe connects with the outer end of the oil supply tube ID, the end of which projects outwardly from the end wall of the surrounding draft tube. v i

In the present embodiment of the invention, oil is also supplied to the interior of the jacket tube ll through a pipe 30, the delivery end of which enters the annular chamber 23 through a port 3|. The oil within the jacket is returned to the preheater 26 through a return pipe 32 which enters the outer end of the preheater at a low point distant from the heating element 21. In order to maintain a higher pressure in the oil supply tube than the general pressure in the preheater drum, a pump 29 is suitably located in the pipe-line 28.

The air duct at its forward end is provided with a surrounding discharge nozzle 33, the walls of which converge forwardly toward the central aperture 34 in order to direct the currents of air inwardly toward the oil discharged through the nozzle 24.

The construction of Fig. 2 involves a simplification of that previously described, in that the relief valve feature is omitted and the fitting 35 simply includes an elbow 36 which receives the forward end of the oil supply tube it for discharge through a duct 31. leading to the nozzle. In order to properly center the fitting, a spider 38 is provided which makes contact with the wall of the draft tube.

In the construction of Fig. 2, the heated oil supplied to the jacket tube H is admitted through an elbow 39 to which the supply pipe 30 is connected, and is returned through a fitting 32 connected with the return line 32.

The air duct is the same as that previously described, but a solenoid check valve 39 is employed in the supply tube I!) to prevent oil from. escaping and dribbling from the nozzle when the burner shuts down.

In the use of the present apparatus for carrying out the features of operation involved in the present method, it is highly desirable to prevent the accumulation, during the off period, of a relatively cold column of oil immediately adjacent the nozzle, in order that, upon ignition, the oil first discharged through the nozzle shall be in a heated condition and of proper viscosity to atomize in the intended manner. A mere preheating of the oil, therefore, at some point distant from the nozzle, and without making adequate provision for the accumulation of heated oil immediately adjacent the nozzle itself, will not adequately subserve the purpose in View, since a preliminary discharge of un heated oil will at the moment of ignition cause improper firing with a resultant fouling of the nozzle and points adjacent thereto. For this reason the present system makes provision for a constant heating of the oil within the supply tube ll? even during the off period, as well as during the ignition period.

The arrangement of the preheater 25 and the supply and return lines to the jacket tube is one which will result in a gravity circulation of heated oil from the preheater even though pressure in the general system through the supply pipe line 25 be out off. This is due to the fact that the pipe 30 to the jacket leads from a high point of greatest heat in the preheater, while the return line enters at a low level, so that the energizing of the heating element 21, or equivalent heating means, will maintain a gravity circulation so that cold oil cannot accumulate in the system in immediate proximity to the nozzle. This is true whether the relief valve be employed or omitted.

Also it will be understood that where the relief valve is employed, a booster pump 29, or the equivalent, is employed for discharging the oil at a higher pressure than that maintained in the general system, so that excess oil admitted through the relief valve will be recirculated through the preheater and its heating effect utilized while passing through the jacket.

Although for purposes of heat conservation it is desirable to employ heated oil from the preheater 26 for circulation through the jacket tube, and although this results in a simplification in structure which is desirable in most cases, I have in mind that, in appropriate circumstances, the fluid (liquid or gaseous) employed for circulation through the jacket, may be derived from some other source, and particularly that heated water may be employed for this purpose, so that in the claims, unless otherwise indicated, it will be understood that the preheating method of the present invention includes the use of some heating fluid other than the same body of oil supplied to the burner.

More particularly directing attention to the operation of the device, in the form here shown by way of exemplification of the above principles of operation, the heated oil under relatively high pressure is admitted through the pipe 28 to the rear end of the oil supply tube It) for discharge through the nozzle. At the same time, the heated oil under low pressure is admitted to the surrounding jacket tube ll, so that the heated condition of the oil will be maintained up to the time of discharge from the nozzle, and the oil passing through the oil tube [0 will be shielded from the cooling effect of the air discharged through the draft tube. At the same time the air itself will be heated to some extent by contact with the heated walls of the jacket tube ll, so that both the oil and the air will be properly conditioned prior to discharge and ignition. Where the relief valve is employed, an excess of pressure will not only be guarded against by the relief valve but the excess oil will be immediately delivered into the heated jacket tube l I, so that the heating effect of this oil will be conserved during its travel through the jacket and prior to its return to the preheater.

The structure as a whole is one which is largely self-contained within the draft tube so that involved pipe connections need not be made. At the same time, by enclosing the operating parts of the device in the manner shown, the heat will be conserved to an advantageous extent and the oil delivered in a condition of proper viscosity. to discharge from the nozzle in the intended manner and in a way which will prevent the deposition of carbon with consequent clogging of the nozzle.

I have not here shown the igniters for the oil, which may be of any approved construction and form no special part of the present invention.

I claim:

1. In an oil burner, the combination of an elongated oil tube, a nozzle at the forward end of said tube, an elongated oil jacket surrounding the oil tube, anda preheater and connections between the oil tube and the upper portion of the preheater and the jacket and adapted'to discharge preheated oil through the oil tube and simultaneously maintain circulation through the jacket tube and back to the lower portion of the preheater, and a relief valve communicating with the oil tube and with the oil jacket and provided with a yieldable valve member adapted under excessive pressure to admit oil from the oil tube to the oil jacket for return circulation therethrough.

2. In' an oil burner, the combination of an elongated oil tube, an elongated oil jacket surrounding the oil tube and affording an annular heating chamber therebetween, a preheater, a pipe connection between the upper portion of the preheater and the rear end of the oil tube, pipe connections between the preheater and opposite ends of the oil jacket for maintaining a circulation of heated oil through the jacket and back to the preheater, a relief valve fitting connected at the forward end of the oil tube and jacket and provided with a valve member adapted under excessive pressure to admit oil from the oil tube into the oil jacket for return circulation therethrough, and an oil discharge nozzle at the forward end of the relief valve fitting.

GLENN F. CROSIAR. 

